Virtual and mixed reality environments provide an immersive, interactive environment where users interact with virtual objects and surroundings. In three-dimensional virtual environments, users view and interact with three-dimensional virtual objects, often with the aid of assistive tools such as glasses, gloves, tracking devices, inertial sensors, body suits and switches. In the real world, however, users observe and interact with real objects without the need for such tools. The user's experience in a virtual environment, therefore, is limited by a lack of realism and a lack of physical feedback from the virtual environment, as well as a lack of natural means for interaction.
In order to enhance the sense of realism, different approaches were taken. Haptics, for example, is an emerging field of technology that adds the sense of touch using tactile feedback to a virtual reality system. The user wearing a tactile feedback device touches a virtual object, then a tactile feedback device provides feedback as if the user touched a real object even though the user did not touch anything in the real world. In addition to visual feedback, tactile feedback adds realism to the virtual experience. However, the user's experience is limited by the requirement of wearing feedback devices.
Virtual reality using only visual feedback has limitations of its own. However, due to the simplicity of the system and the latest technological development in imaging and computing technologies, more realistic vision-based virtual and mixed reality systems have been developed.
For example, EON I-Cube by EON Reality of Irvine, Calif. and Automated Virtual Environment by Fakespace Inc. of Marshalltown, Iowa display virtual objects onto a screen surrounding the user. Through the use of specialized glasses, the user is able to visualize computer-processed information in three dimensions. Supplemental inertial pointing devices allow the users to navigate and interact with the virtual world.
In other virtual reality systems such as Varrier Autostereoscopic Virtual Reality Display by the University of Illinois at Chicago, a user is presented with a partially immersive array of three-dimensional screens that display information without the need for special eyewear. However, peripheral devices are still required to interact with the virtual world.
A three-dimensional time-of-flight (TOF) sensor calculates the time-of-flight of light from a light source to the sensor and measures the distance to an object by reflecting light. The time difference is converted to the distance information when the speed of light is known, thereby measuring the distance from the sensor to the object. Three-dimensional TOF sensors have been developed by Canesta Inc. of San Jose, Calif., CSEM of Switzerland, and 3DV Systems of Yokneam, Israel.
It would be useful and beneficial to have a system that would allow users to interact with the virtual world by three-dimensional visual feedback without the need for having peripheral devices.